The present invention relates to power line communication (PLC). It finds particular application in conjunction with PLC used on heavy vehicles having a 24 volt electrical architecture and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
PLC is used by industry in North America on heavy vehicles as a solution for trailer-tractor communication in articulated vehicles. An electronic control unit (ECU) on the trailer transmits a PLC signal on a 12 volt electrical power line supplied by the tractor. The signal is defined by SAE Recommended Practice J2497, and commands a trailer antilock braking system (ABS) malfunction indicator located in the tractor. More specifically, an ignition input pin of an ABS ECU on the tractor receives the PLC signal and controls the trailer ABS malfunction indicator by either illuminating or extinguishing the indicator. The ECU on the tractor typically includes two (2) electrical power pins: a battery input pin, which always receives 12 volt electrical power from a battery on the vehicle, and an ignition input pin, which receives 12 volt electrical power when the vehicle ignition is engaged. Electrical power received by the battery input pin powers one portion (e.g., a main portion) of the ECU, while power received by the ignition input pin is used to power another portion of the ECU (e.g., microelectronics such as a microcontroller in the ECU). PLC signals are also received by the ECU on the tractor via the ignition input pin.
The PLC signal is subject to attenuation or interference from, for example, powering the microelectronics on the ECU, and stringent testing is required to ensure acceptable performance. In that regard, PLC signals are typically only reliable on a power line of up to a voltage of ˜18 volts. Therefore, vehicles requiring PLC have an electrical architecture using less than 18 volts (e.g., 12 volts in North America).
It is desirable to use PLC on towing vehicles (e.g., tractors and straight trucks) having a 24 volt electrical architecture that will tow trailers having an electrical architecture less than 18 volts (e.g., 12 volts).
The present invention provides a new and improved apparatus and method for PLC communication on a vehicle with a dual voltage architecture.